X0306 4 2021-05-26 0 0001595974 MAGNITE, INC. MGNI 0001700262 Evans Katie Seitz C/O MAGNITE, INC. 6080 CENTER DRIVE, 4TH FLOOR LOS ANGELES CA 90045 0 1 0 0 Chief Operating Officer Common Stock 2021-05-26 4 M 0 1442 3.96 A 380902 D Common Stock 2021-05-26 4 M 0 2884 4.64 A 383786 D Common Stock 2021-05-26 4 M 0 2884 4.64 A 386670 D Common Stock 2021-05-26 4 M 0 7212 5.46 A 393882 D Common Stock 2021-05-26 4 M 0 5410 7.74 A 399292 D Common Stock 2021-05-26 4 M 0 22971 3.95 A 422263 D Stock Option (Right to Buy) 3.96 2021-05-26 4 M 0 1442 0.00 D 2021-06-08 Common Stock 1442 0 D Stock Option (Right to Buy) 4.64 2021-05-26 4 M 0 2884 0.00 D 2022-07-26 Common Stock 2884 0 D Stock Option (Right to Buy) 4.64 2021-05-26 4 M 0 2884 0.00 D 2022-07-19 Common Stock 2884 0 D Stock Option (Right to Buy) 5.46 2021-05-26 4 M 0 7212 0.00 D 2023-03-05 Common Stock 7212 0 D Stock Option (Right to Buy) 7.74 2021-05-26 4 M 0 5410 0.00 D 2023-07-31 Common Stock 5410 0 D Stock Option (Right to Buy) 3.95 2021-05-26 4 M 0 22971 0.00 D 2023-12-05 Common Stock 2291 0 D Immediately exercisable. /s/ Aaron Saltz, attorney-in-fact 2021-05-28